Cleaning seawater sprayed filters

The title says it all: How do I clean a Calumet/Hoya multicoated glass filter that has been lighly sprayed by seawater? I tried a bit with a lens cloth and just smeared the mess. I hope it did not damage the coating or the glass. Since regular lens liquids cannot be used, should I look for an exotic hard-to-find chemical or can I get by with a simpler technique?

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Ari,
Use distilled water. Sea water leaves behind a residue of salt, minerals and organic matter. The distilled water will rehydrate the residue. Rinse the residue off. shake off as much of the distilled water as possible. Gently dry with lens tissue.

Being as the salt spray is already well dried, I'd use plain water, perhaps with a bit of gentle detergent to rehydrate, and dissolve the salts, as Helen suggested. Just let the water and drop of detergent pool on the filter, swish it around a bit after a few minutes, and then rinse well with tap water before applying a soft lens cloth.

[COLOR=SlateGray]"You can't depend on your eyes if your imagination is out of focus." -Mark Twain[/COLOR]

Not to be a stickler, but I'd be careful with Tap Water. What comes out of the tap varies greatly throughout the world. In many locations the tap water is very hard with high levels of mineral salts. Generally not the best to use on the soft coatings of filters.

This is not a problem for me in the SF Bay Area because we get very pure, soft water siphoned from the Yosemite Valley. It WAS definitely a problem when I lived in the Las Vegas Valley and the California Central Valley. That was nearly 20 years ago, but the hard water in those areas left more residue than it removed! In recent times, I have been at locations in the Southwest and the Midwest and I can attest to the fact that in many of those locations the water has high mineral salt contents.

Now, for English water, I have to segue to my beer brewing. I dump a "Hell of a lot" of mineral salts to replicate English tap waters to make British ales.
The mineral concoction is commonly called "Burton Water salts".

I do agree with Ralph that sometimes a dish detergent will help, especially where there are organic and/or oily residues.
YMMV,
Geary

I work with glass a great amount and always recommend using distilled or bottled water to ensure your not introducing any more salts or minerals than are already there.

Never wipe or rub the filter with a cloth, without first soaking or at least rinsing the filter with fresh water, I normally use fresh warm water if available and a can of air to blow dry the filter.

I shoot in Yellowstone national park alot, and the geysers are heavy with minerals, I always carry plastic containers with me that I can fill with distilled water and soak the filter in case of contanimation, I then rinse and blow off with canned air and then let air dry.

One of the biggest problems with wiping filters that have been sprayed is you will drive the minerals into the filter ring, which can cause corrosion to form under the ring, and you will almost always scratch the coating. I also use a very mild dish soap, as we do with our ground glass screen to help 'float' the contamination away.

You're correct, Geary, I should have been more clear about the tap water being only for rinsing off the water/detergent mix prior to conventional cleaning. Distilled or bottled water would be far better as a rinse, and less likely to have either dissolved minerals or particulate contamination.

[COLOR=SlateGray]"You can't depend on your eyes if your imagination is out of focus." -Mark Twain[/COLOR]

The soft "Lifeventure" towels available from outdoor shops are great for covering the camera in rain and spray and are also soft enough to wipe the filter. They are much thicker and more absorbent than lens cloths yet very soft. I use one with my Lee resin filters quite happily, so should be fine for your Hoya glass one. Best to remove spray before it dries, otherwise concur soaking with deionised water before wiping.
In misty/spray conditions, I insert another filter in the front slot which gets removed (covered in any spray) just before making the exposure.

I have used watery soap in the past to clean finger-oil off filters, followed by tap water, followed by distilled water and dry by hairdrier: glad to see I wasn't doing anything too silly...

Now, for English water, I have to segue to my beer brewing. I dump a "Hell of a lot" of mineral salts to replicate English tap waters to make British ales.
The mineral concoction is commonly called "Burton Water salts

Don't forget to add enough chlorine to make you drink the water holding your nose shut & flouride (whether you want it or not)... Actually, I'm tickled pink you can actually buy a product designed reproduce English water - I hope it's to reproduce spring/stream water rather than the stuff that comes out my tap though!

Why should water that is high in mineral salts affect filter coatings any more than distilled water? In most of the situations that I've been in when my cameras have been sprayed with seawater or mud the chances of finding distilled water have been nil. It's more important to get the stuff off quickly in the freshest water you have available.

Best,
Helen
All this talk of seawater makes me wonder how many sailors there are on the forum. I enjoy sailing, and have a little yawl built in 1896. Bill Tillman, who I met a few times, is probably my all-time hero and role model. He was a bit more talkative than I am, though.